66 



ACTINIARIA 



Fig. 81 



Temp, at the bottom 2,5° (Sw. Spitzb.-Exp. 1908, St. 51, 2 sp.) Temple bay, Bio- 



na's haven, 30 m. Compact greyish-red clay with stones. Temp, at the bottom 



3,78° (Sw. Spitzb.-Exp. 1908, St. 56, 2 sp.). Spitzbergen without distinct locality 



(Sw. Spitzb.-Exp. 1898). 



Exterior aspect: The physa, if present, is small, in as much as only the most proximal part of 



the column is devoid of a cuticle. On the scapus there are 8 shallow, longitudinal furrows, corresponding 



to the insertions of the mesenteries and particularlj^ distinct in the distal part. In contracted state of the 



animal the inV'Olved part of the scapus is 



polygonal. The cuticle of the scapus is, in 

 comparison with the other Milne-Edward- 

 sz«-species, feebly developed and some- 

 times here and there lost. In the spec- 

 imen collected by Roemer and Schau- 

 dinn there are fragments of yellowish- 

 \ brown particles and small grains of sand 

 sticking to the undermost part of the sca- 

 pus. I have not been able to observ^e any 

 of the "//fl/c«w/)a-papillae" which exist in 

 the genus Paraedwardsia, and therefore the 

 gland-cells have probably served as organs 

 of attachment. The capitulum is short, in 

 the proximal part polygonal, in the distal 

 part in transverse-sections more round. Pro- 

 bably this difference is due to a various 



rig. So. 



Textfig. 80 — 82. Mitne-Edwardsia polaris. 



Fig. 80: Transverse section of a parietal muscle in the upper part of the glan 



dular tract. Fig. 81 : Transverse section of a pennon in the same tract. Fig. 82 



Section of scapus -with groups of nematocysts (n). 



state of contraction of the different parts. The tentacles are not more than 12, on one specimen I observed 

 tliat the two tentacles projecting from the ventro-lateral compartmetits are smaller than the others. The 

 oral disc is inconsiderable, the actinopharynx is short and furnished with 8 longitudinal ridges at the in- 

 sertions of the mesenteries; between the ridges there are deep longitudinal furrows. An indication of a 

 ventral siphonoglyphe seems to be found (the specimens were, howe\-er, not so well preserved that I can 

 state this with certainty). 



Anatomical description: The ectoderm of the scapus is now thin, now more thick, especially 

 in the parts containing nematocysts. The cuticle is weak, especially in comparison with that of M. loveni 

 and carnea. The nematocysts which in the scapus-ectoderm reach a size of (14) 17 — 22 X 2, 5 — 3 (3,5) n 

 are here a little numerous and packed together in groups, scattered between the insertions of the mesen- 

 teries and, on account of the thickening of the ectoderm, sometimes sunk a little down in the mesogloea 

 (textfig. 82). The mesogloea is of about the same thickness as the ectoderm, the endoderm is however thin- 

 ner. The high ectoderm of the capitulum contains nematocysts, 14 — 17 fi long, arranged on the ridges. In the 

 parts of the involved cai)itulum which are the most closely pressed together the mesogloea forms high ridges 



